The present invention concerns generally the sealing of the connection of radially spaced pipes.
In center pivot farm irrigation systems a centrally located pivot structure may include a fixed pipe elbow having an upper end in communication with a vertically disposed pipe which rotates about a vertical axis as the several towers and the horizontal distribution pipe carried thereby swing about the field being irrigated. The tower carried horizontal delivery pipe is equipped with spaced apart nozzles. During system operation previous gaskets between the rotating and fixed concentric pipes were subject to leaking. A study of the problem of leakage indicated that it was occuring between the outer or back surface of the gasket and the outer or fixed pipe in which the gasket was installed. Prior gaskets for such a use included the chevron shaped gasket having a single annular lip of tapered configuration viewed in section.
In the development of the present gasket consideration was given to resistance to abrasion from sand and other particles in well water supplied to the irrigation system, extreme temperatures, exposure to chemicals added to irrigation system water and pressures ranging from 10 psi to 120 psi.